ARTICLE: Judge Drops Charges From Blackwater Deaths in Iraq, By CHARLIE SAVAGE, New York Times, December 31, 2009

Correct me if I'm wrong, but it almost seems like the big mistake here was the lack of (a href="http://en.wikipedia.org/wiki/Miranda_warning">"Mirandizing" the suspects, in the sense that the State Department told the Blackwater guys that what they said couldn't be used against them in a court of law--and then it was. According to the story:

The guards could not be prosecuted under Iraqi law because of an immunity agreement that had been signed by the Coalition Provisional Authority, the governing authority installed by the United States after the invasion of Iraq. But American prosecutors knew from the beginning that they were facing a difficult task in bringing the case. Complications included the applicability of federal statutes to the guards because they were working overseas at the time for the State Department, and the significant problem stemming from statements the guards gave shortly after the shootings. The guards had been told by State Department investigators that they could be fired if they did not talk about the case, but that whatever they said would not be used against them in any criminal proceeding. Nevertheless, Judge Urbina found that "in their zeal to bring charges," investigators and prosecutors had extensively used those statements, disregarding "the warning of experienced, senior prosecutors" that "the course of action threatened the viability of prosecution."

Problems and issues remain, and yet, in the absence of some larger and yet more specific (to the environment) rule set on employing private security guards on behalf of U.S. public officials abroad, it can be said that our domestic default system worked as it was designed to, in that it leaned more to protecting the rights of the accused than facilitating rushed prosecutions.